1. Field of the Invention
The present invention relates to a drainage collective pipe joint where wastewater flowing in a collective housing of multiple floors is subjected to swirl flow and is allowed to flow down.
2. Description of the Prior Art
In the prior art, a drainage collective pipe joint to be used in air vent pipe arrangement structure of single pipe type comprises an upper vertical pipe connection port, a main body part having a taper pipe part and a lower vertical pipe connection port connected in the axial direction. The main body part is provided with at least one horizontal branch pipe connection port. Sewage or wastewater from each floor is allowed to flow in through the horizontal branch pipe, and is joined with that flowing in from the upper vertical pipe, and swirl flow is formed and the joined flow is allowed to flow down into a lower floor.
As such swirl flow forming means, for example, JP-B 62-50517 is disclosed where a deflecting plate is provided to a main body part just below an upper vertical pipe connection port, and a taper pipe part is provided with a plurality of vanes having slant angle for swirl motion and arranged in rotary symmetry.
According to such swirl flow forming means, wastewater from the upper vertical pipe is deflected in one direction by the deflecting plate and collides with the inner circumferential wall of the main body part and scatters and falls to the taper pipe part. Also wastewater from the horizontal branch pipe falls to the taper pipe part and is caught by the vanes in the taper pipe part and the wastewater caught there flows down along the vanes and is supplied with the swirling property and becomes the swirl flow.
According to the swirl flow, the vent core passing through the upper and lower vertical pipes within the drainage collective pipe joint is formed in the wastewater flow, and circulation of air in the drain pipe system is intended thereby variation of the air pressure within the upper and lower vertical pipes is suppressed.
In such a drainage collective pipe joint in conventional structure, however, wastewater flowing from the upper vertical pipe is deflected in one direction by the deflecting plate and collides with the inner circumferential wall of the main body part and flows down. Therefore when the horizontal branch connection port is provided at the opposite side of the deflecting plate, a problem occurs in that the deflected wastewater as above described flows reversely into the horizontal branch pipe.
Consequently in the drainage collective pipe joint, it is usually avoided that the horizontal branch pipe connection ports are provided in four directions at intervals of 90 degrees in the circumferential direction, but the horizontal branch drain pipe connection ports are provided in two or three directions except for the opposite side to the deflecting plate.
Also a problem occurs in that the deflected wastewater bounces back at the inner circumferential wall of the main body part, and flows reversely into also the horizontal branch pipe connection port provided at the side other than the opposite side of the deflecting plate.
Also the vanes for deflection has limitation in the slant angle from the viewpoint of prevention of the water plug phenomenon in the taper pipe part. Therefore further improvement in providing the swirling property has been desired.